Domcomp - No-nonsense domain price comparisons, updated daily
Book Flee - Compare prices of books from iTunes and Amazon easily.
Pricepeek - Compare prices of the same product across all Amazon locales
bbboookkksss - An super simple way to find great books at low prices
The Mac Index - Compare Apple product prices in different countries
dofo.com - Domain search platform Dofo.com gathers all registered (350 million) domains of the world in a single place. Dofo also brings together all the domain names that are on sale, provides useful features, all completely free.